??? Patient with knee pain during passive hip and knee flexion

[John W]

I have a patient 15 weeks s/p THR. I've been working with her for a few weeks, but she continues to have pain in the anterior aspect of the knee when I flex her knee and follow that with hip flexion to about 100 degrees. She has no knee pain when I perform full knee flexion with overpressure when the hip is bent 45 degrees. There's something about adding the hip flexion that provokes pain in the front of the knee and into the proximal tibia. She describes it as burning/pulling.

What neurodynamically is most likely to get tensioned with this maneuver?

[garydiny]

Femoral nerve compression at the hip with 100 deg hip flex?
Peroneal nerve branching with flexion of hip, though not sure as to why the knee flexion would then provoke, unless that causes more compressive vs. tension stress.
Lumbar spine involvement in 100 deg hip flexion

Interesting, I think varying sequence of movements might shed some light as to the 'source'. Keep us posted as to any differentiating movements or testing from neurodynamics perspective.

Gary

[Diane]

Thre are several cutaneous branches of the femoral nerve that drape down over the patella. I'd consider one or more of those may be sensitized.

[John W]

Thre are several cutaneous branches of the femoral nerve that drape down over the patella. I'd consider one or more of those may be sensitized.

Diane,
Why/How would the addition of hip flexion neurodynamically provoke femoral nerve branches in an already flexed knee?

I am wondering about femoral nerve compression, however. She had the rare anterolateral, "micro" incision-approach (important detail?). It's strange that she experiences a burning/pulling as I slowly add hip flexion, though.

[Diane]

Originally Posted by John W

Diane,
Why/How would the addition of hip flexion neurodynamically provoke femoral nerve branches in an already flexed knee?

I am wondering about femoral nerve compression, however. She had the rare anterolateral, "micro" incision-approach (important detail?). It's strange that she experiences a burning/pulling as I slowly add hip flexion, though.

It might be just a specific pull at the top of the nerve. Nerves are single cells with very long axons, remember. They can "feel" things anywhere along their length. Sometimes "pain" can even be felt in the brain representation of the other side of the body, in its paired twin. I'd clean up the cutaneous twigs that have to get through/past the inguinal ligament (maybe the ones to her particular knee branch off femoral nerve higher than inguinal ligament), then try again with the hip/knee flexion sensitivity test.

[emad]

The Saphenous nerve supplies anterior knee.

cheers
Emad

[TexasOrtho]

I'd say check the saphenous n as well John. I wonder if frontal plane motions have any effect on the knee pain during hip flexion? You could flex her hip from a position of relative abduction and see if there is a difference. Just spitballing.

This is a good opportunity for me to go back and review saphenous n anatomy.

[Diane]

Originally Posted by emad

The Saphenous nerve supplies anterior knee.

cheers
Emad

Sure, but not the entire knee.
The joint is innervated by a branch of some nerve at the back. The front is supplied by three or four cutaneous nerves with names like "anterior femoral cutaneous", "anterio-medial cutaneous", and so on. The lateral side is supplied by long branches of the lateral femoral cutaneous, a different nerve, not femoral. The back likewise, posterior cutaneous. The saphenous only supplies the medio-inferior aspect of the knee. There is a nice anastomosis of various branches of the cutaneous supply to the knee, over the patella. This anastomosis probably helps the brain figure out position sense - mechanically there will be more tug through one or another, depending on which way the patella is pulling.